1. Field of the Invention
The present invention relates generally to electrochemical cells and, more particularly, to electrical terminal connections for such cells. Specifically, the present invention relates to an improved electrical terminal connection for electrochemical cells useful particularly in aerospace applications.
2. Description of the Prior Art
Electrochemical cells are available, in a wide variety of types, shapes and forms. In certain applications, electrochemical cells are encased within a sealed metal vessel. Such sealed vessels require electrical terminal connectors which pierce the vessel and provide terminal connection from the exterior of the containment vessel to the plate stacks contained therein. Examples of metal gas cells that utilize such terminal connectors are illustrated in U.S. Pat. No. 4,950,564 and U.S. Pat. No. 5,002,842, the contents of which are specifically incorporated herein by reference.
In many applications, the electrochemical cell electrolyte is relatively corrosive to certain metal components. Examples of such electrolyte systems include aqueous systems and alkaline electrolytes such potassium hydroxide (KOH). Previous hereto, one of the primary considerations for selecting a material and design for an electrical terminal is that it be inert to the chemical environment within the electrochemical cell. Consequently, electrical conductivity, weight and other factors were considered as secondary compared to the inertness factor. Unfortunately, such inert materials have tended to be somewhat heavy, and in certain instances such as in aerospace applications, weight is always an extremely critical factor. In other instances, the materials selected for use in the terminals were not necessarily the most electrically conductive compared to other available materials. This has been particularly true in nickel hydrogen secondary electrochemical cells for aerospace applications, as exemplified in the above-referenced patents. In such applications, high conductivity and light weight are critical factors, although the cell environment is also somewhat corrosive. Therefore, there remains a need for electrochemical electrical terminal connectors which can satisfy both inertness to the electrochemical cell environment as well as provide reduced weight and increased conductivity.